Don't build the archived signature on the association
Don't build the archived signature on the association

This will add it to the in-memory association cache which will
result in millions of signatures being cached in memory.

alphagov/e-petitions,oskarpearson/e-petitions,StatesOfJersey/e-petitions,joelanman/e-petitions,joelanman/e-petitions,StatesOfJersey/e-petitions,StatesOfJersey/e-petitions,unboxed/e-petitions,oskarpearson/e-petitions,alphagov/e-petitions,oskarpearson/e-petitions,unboxed/e-petitions,unboxed/e-petitions,unboxed/e-petitions,alphagov/e-petitions,joelanman/e-petitions,StatesOfJersey/e-petitions,alphagov/e-petitions